/*
*  linux/kernel/tty_io.c
*
*  (C) 1991  Linus Torvalds
*/

/*
* 'tty_io.c' gives an orthogonal feeling to tty's, be they consoles
* or rs-channels. It also implements echoing, cooked mode etc.
*
* Kill-line thanks to John T Kohl.
*/
#include <ctype.h>
#include <errno.h>
#include <signal.h>

#define ALRMMASK (1<<(SIGALRM-1))
#define KILLMASK (1<<(SIGKILL-1))
#define INTMASK (1<<(SIGINT-1))
#define QUITMASK (1<<(SIGQUIT-1))
#define TSTPMASK (1<<(SIGTSTP-1))

#include <linux\sched.h>
#include <linux\tty.h>
#include <asm\segment.h>
#include <asm\system.h>

#define _L_FLAG(tty,f)	((tty)->termios.c_lflag & f)
#define _I_FLAG(tty,f)	((tty)->termios.c_iflag & f)
#define _O_FLAG(tty,f)	((tty)->termios.c_oflag & f)

#define L_CANON(tty)	_L_FLAG((tty),ICANON)
#define L_ISIG(tty)		_L_FLAG((tty),ISIG)
#define L_ECHO(tty)		_L_FLAG((tty),ECHO)
#define L_ECHOE(tty)	_L_FLAG((tty),ECHOE)
#define L_ECHOK(tty)	_L_FLAG((tty),ECHOK)
#define L_ECHOCTL(tty)	_L_FLAG((tty),ECHOCTL)
#define L_ECHOKE(tty)	_L_FLAG((tty),ECHOKE)

#define I_UCLC(tty)		_I_FLAG((tty),IUCLC)
#define I_NLCR(tty)		_I_FLAG((tty),INLCR)
#define I_CRNL(tty)		_I_FLAG((tty),ICRNL)
#define I_NOCR(tty)		_I_FLAG((tty),IGNCR)

#define O_POST(tty)		_O_FLAG((tty),OPOST)
#define O_NLCR(tty)		_O_FLAG((tty),ONLCR)
#define O_CRNL(tty)		_O_FLAG((tty),OCRNL)
#define O_NLRET(tty)	_O_FLAG((tty),ONLRET)
#define O_LCUC(tty)		_O_FLAG((tty),OLCUC)

struct tty_struct tty_table[] = {
	{
		{
			ICRNL,					/* change incoming CR to NL */
			OPOST | ONLCR,			/* change outgoing NL to CRNL */
			0,
			ISIG | ICANON | ECHO | ECHOCTL | ECHOKE,
			0,						/* console termio */
			INIT_C_CC
		},
		0,							/* initial pgrp */
		0,							/* initial stopped */
		con_write,
		{ 0, 0, 0, 0, "" },			/* console read-queue */
		{ 0, 0, 0, 0, "" },			/* console write-queue */
		{ 0, 0, 0, 0, "" }			/* console secondary queue */
	},
	{
		{
			0,						/* no translation */
			0,						/* no translation */
			B2400 | CS8,
			0,
			0,
			INIT_C_CC
		},
		0,
		0,
		rs_write,
		{ 0x3f8, 0, 0, 0, "" },		/* rs 1 */
		{ 0x3f8, 0, 0, 0, "" },
		{ 0, 0, 0, 0, "" }
	},
	{
		{
			0,						/* no translation */
			0,						/* no translation */
			B2400 | CS8,
			0,
			0,
			INIT_C_CC
		},
		0,
		0,
		rs_write,
		{ 0x2f8, 0, 0, 0, "" },		/* rs 2 */
		{ 0x2f8, 0, 0, 0, "" },
		{ 0, 0, 0, 0, "" }
	}
};

/*
* these are the tables used by the machine code handlers.
* you can implement pseudo-tty's or something by changing
* them. Currently not done.
*/
struct tty_queue * table_list[] = {
	&tty_table[0].read_q, &tty_table[0].write_q,
	&tty_table[1].read_q, &tty_table[1].write_q,
	&tty_table[2].read_q, &tty_table[2].write_q
};

void tty_init(void)
{
	rs_init();
	con_init();
}

void tty_intr(struct tty_struct * tty, int mask)
{
	int i;

	if (tty->pgrp <= 0)
		return;
	for (i = 0; i < NR_TASKS; i++)
		if (task[i] && task[i]->pgrp == tty->pgrp)
			task[i]->signal |= mask;
}

static void sleep_if_empty(struct tty_queue * queue)
{
	cli();
	while (!current->signal && EMPTY(*queue))
		interruptible_sleep_on(&queue->proc_list);
	sti();
}

static void sleep_if_full(struct tty_queue * queue)
{
	if (!FULL(*queue))
		return;
	cli();
	while (!current->signal && LEFT(*queue) < 128)
		interruptible_sleep_on(&queue->proc_list);
	sti();
}

void wait_for_keypress(void)
{
	sleep_if_empty(&tty_table[0].secondary);
}

void copy_to_cooked(struct tty_struct * tty)
{
	signed char c;

	while (!EMPTY(tty->read_q) && !FULL(tty->secondary)) {
		GETCH(tty->read_q, c);
		if (c == 13)
			if (I_CRNL(tty))
				c = 10;
			else if (I_NOCR(tty))
				continue;
			else;
		else if (c == 10 && I_NLCR(tty))
			c = 13;
		if (I_UCLC(tty))
			c = tolower(c);
		if (L_CANON(tty)) {
			if (c == KILL_CHAR(tty)) {
				/* deal with killing the input line */
				while (!(EMPTY(tty->secondary) ||
					(c = LAST(tty->secondary)) == 10 ||
					c == EOF_CHAR(tty))) {
					if (L_ECHO(tty)) {
						if (c < 32)
							PUTCH(127, tty->write_q);
						PUTCH(127, tty->write_q);
						tty->write(tty);
					}
					DEC(tty->secondary.head);
				}
				continue;
			}
			if (c == ERASE_CHAR(tty)) {
				if (EMPTY(tty->secondary) ||
					(c = LAST(tty->secondary)) == 10 ||
					c == EOF_CHAR(tty))
					continue;
				if (L_ECHO(tty)) {
					if (c < 32)
						PUTCH(127, tty->write_q);
					PUTCH(127, tty->write_q);
					tty->write(tty);
				}
				DEC(tty->secondary.head);
				continue;
			}
			if (c == STOP_CHAR(tty)) {
				tty->stopped = 1;
				continue;
			}
			if (c == START_CHAR(tty)) {
				tty->stopped = 0;
				continue;
			}
		}
		if (L_ISIG(tty)) {
			if (c == INTR_CHAR(tty)) {
				tty_intr(tty, INTMASK);
				continue;
			}
			if (c == QUIT_CHAR(tty)) {
				tty_intr(tty, QUITMASK);
				continue;
			}
		}
		if (c == 10 || c == EOF_CHAR(tty))
			tty->secondary.data++;
		if (L_ECHO(tty)) {
			if (c == 10) {
				PUTCH(10, tty->write_q);
				PUTCH(13, tty->write_q);
			}
			else if (c < 32) {
				if (L_ECHOCTL(tty)) {
					PUTCH('^', tty->write_q);
					PUTCH(c + 64, tty->write_q);
				}
			}
			else
				PUTCH(c, tty->write_q);
			tty->write(tty);
		}
		PUTCH(c, tty->secondary);
	}
	wake_up(&tty->secondary.proc_list);
}

int tty_read(unsigned channel, char * buf, int nr)
{
	struct tty_struct * tty;
	char c, *b = buf;
	int minimum, time, flag = 0;
	long oldalarm;

	if (channel > 2 || nr < 0) return -1;
	tty = &tty_table[channel];
	oldalarm = current->alarm;
	time = 10L * tty->termios.c_cc[VTIME];
	minimum = tty->termios.c_cc[VMIN];
	if (time && !minimum) {
		minimum = 1;
		if (flag = (!oldalarm || time + jiffies<oldalarm))
			current->alarm = time + jiffies;
	}
	if (minimum>nr)
		minimum = nr;
	while (nr > 0) {
		if (flag && (current->signal & ALRMMASK)) {
			current->signal &= ~ALRMMASK;
			break;
		}
		if (current->signal)
			break;
		if (EMPTY(tty->secondary) || (L_CANON(tty) &&
			!tty->secondary.data && LEFT(tty->secondary) > 20)) {
			sleep_if_empty(&tty->secondary);
			continue;
		}
		do {
			GETCH(tty->secondary, c);
			if (c == EOF_CHAR(tty) || c == 10)
				tty->secondary.data--;
			if (c == EOF_CHAR(tty) && L_CANON(tty))
				return (b - buf);
			else {
				put_fs_byte(c, b++);
				if (!--nr)
					break;
			}
		} while (nr > 0 && !EMPTY(tty->secondary));
		if (time && !L_CANON(tty))
			if (flag = (!oldalarm || time + jiffies < oldalarm))
				current->alarm = time + jiffies;
			else
				current->alarm = oldalarm;
		if (L_CANON(tty)) {
			if (b - buf)
				break;
		}
		else if (b - buf >= minimum)
			break;
	}
	current->alarm = oldalarm;
	if (current->signal && !(b - buf))
		return -EINTR;
	return (b - buf);
}

int tty_write(unsigned channel, char * buf, int nr)
{
	static cr_flag = 0;
	struct tty_struct * tty;
	char c, *b = buf;

	if (channel > 2 || nr<0) return -1;
	tty = channel + tty_table;
	while (nr>0) {
		sleep_if_full(&tty->write_q);
		if (current->signal)
			break;
		while (nr > 0 && !FULL(tty->write_q)) {
			c = get_fs_byte(b);
			if (O_POST(tty)) {
				if (c == '\r' && O_CRNL(tty))
					c = '\n';
				else if (c == '\n' && O_NLRET(tty))
					c = '\r';
				if (c == '\n' && !cr_flag && O_NLCR(tty)) {
					cr_flag = 1;
					PUTCH(13, tty->write_q);
					continue;
				}
				if (O_LCUC(tty))
					c = toupper(c);
			}
			b++; nr--;
			cr_flag = 0;
			PUTCH(c, tty->write_q);
		}
		tty->write(tty);
		if (nr > 0)
			schedule();
	}
	return (b - buf);
}

/*
* Jeh, sometimes I really like the 386.
* This routine is called from an interrupt,
* and there should be absolutely no problem
* with sleeping even in an interrupt (I hope).
* Of course, if somebody proves me wrong, I'll
* hate intel for all time :-). We'll have to
* be careful and see to reinstating the interrupt
* chips before calling this, though.
*
* I don't think we sleep here under normal circumstances
* anyway, which is good, as the task sleeping might be
* totally innocent.
*/
void do_tty_interrupt(int tty)
{
	copy_to_cooked(tty_table + tty);
}

void chr_dev_init(void)
{
}
